Backport PR matplotlib#17602: FIX: propagate _is_saving state when changing canvases

QuLogic · tacaswell · commit 6afbad448f9a · 2020-06-10T11:23:01.000-04:00
Merge pull request matplotlib#17602 from tacaswell/fix_mixed_canvas_animation_save FIX: propagate _is_saving state when changing canvases Conflicts: lib/matplotlib/backend_bases.py - other nearby changes, only backport the context manager related changes lib/matplotlib/tests/test_figure.py - did not backport the other tests that are currently only on master branch.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -2068,8 +2068,9 @@ def print_figure(self, filename, dpi=None, facecolor=None, edgecolor=None,
         # Some code (e.g. Figure.show) differentiates between having *no*
         # manager and a *None* manager, which should be fixed at some point,
         # but this should be fine.
-        with cbook._setattr_cm(self, _is_saving=True, manager=None), \
-                cbook._setattr_cm(self.figure, dpi=dpi):
+        with cbook._setattr_cm(self, manager=None), \
+                cbook._setattr_cm(self.figure, dpi=dpi), \
+                cbook._setattr_cm(canvas, _is_saving=True):
 
             if facecolor is None:
                 facecolor = rcParams['savefig.facecolor']
diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -487,3 +487,12 @@ def test_removed_axis():
     fig, axs = plt.subplots(2, sharex=True)
     axs[0].remove()
     fig.canvas.draw()
+
+
+@check_figures_equal(extensions=["svg", "pdf", "eps", "png"])
+def test_animated_with_canvas_change(fig_test, fig_ref):
+    ax_ref = fig_ref.subplots()
+    ax_ref.plot(range(5))
+
+    ax_test = fig_test.subplots()
+    ax_test.plot(range(5), animated=True)
